Association between omega-3 fatty acids intake and muscle strength in older adults: A study from National Health and Nutrition Examination Survey (NHANES) 1999–2002

Background Muscle strength is a predictor of mortality in older adults and some dietary components are associated with this variable; however, little is known about the association between omega-3 fatty acids (ω-3) intake and strength in older adults. Objective To assess whether ω-3 intake is associated with muscle strength in individuals over 50 years. We also aimed to evaluate whether an isocaloric substitution of dietary fatty acids types by ω-3 intake could be associated with muscle strength. Methods This study included older adults aged from 50 to 85 y, from National Health and Nutrition Examination Survey (NHANES) 1999–2000 and 2001–2002. A total of 2141 individuals (1119 men and 1022 women) were evaluated and provided complete and reliable dietary intake and isokinetic strength of the knee extensors (peak force) data. Linear regression analysis was conducted without (Model 1) and with adjustments (Model 2). Isocaloric substitution analysis was performed to evaluate whether the substitution of polyunsaturated (excluding ω-3), monounsaturated, saturated fats and ω-6 by consumption of ω-3 is associated with strength. Results Total ω-3, docosahexaenoic acid (DHA), eicosapentaenoic acid (EPA) and alpha-linolenic acid (ALA) intakes were positively associated with peak force in men (Model 1). However, after the adjustments for confounders (Model 2), only total ω-3 intake remained significant. Ω-3 intake was not associated with strength in women. The isocaloric substitution of saturated, polyunsaturated, monounsaturated fats and ω-6 by ω-3 was not associated with peak force. Conclusion The intake of total ω-3 was positively associated with muscle strength in older men, but not in older women. In addition, the substitution of other fatty acids by ω-3 intake was not associated with strength.